UITableView background colour for bottom 5 rows

Question

I do know how to input background colours for my row, but I don't really know how I can filter it by only the bottom 5 rows are "cell.backgroundColor = UIColor.red;" whereas the rest stays the same. Appreciate those who can help me this thanks!

P.S: Sorry as my swift is quite rusty.

UITableView Controller

    import UIKit
    import FirebaseDatabase


    var postData2 = [String]()
    var postData3 = [String]()
     var tableDataArray = [tableData]()



    class ResultsController: UITableViewController {


        override func viewDidLoad() {
            super.viewDidLoad()

            ref = Database.database().reference() //set the firebase reference
            // Retrieve the post and listen for changes
            databaseHandle = ref?.child("Posts3").observe(.value, with: { (snapshot) in
                postData2.removeAll()
                postData3.removeAll()
                tableDataArray.removeAll()

                for child in snapshot.children {
                    let snap = child as! DataSnapshot
                    let key = snap.key
                    let value = String(describing: snap.value!)
                    let rating = (value as NSString).integerValue


                    postData2.append(key)
                    postData3.append(value)
                    tableDataArray.append(tableData(boothName: key, boothRating: rating))


                }
                postData2.removeAll()
                postData3.removeAll()
                let sortedTableData = tableDataArray.sorted(by: { $0.boothRating > $1.boothRating })
                for data in sortedTableData {
                    postData2.append(data.boothName)

                    let value = String(describing: data.boothRating)
                    postData3.append(value)
                }

                self.tableView.reloadData()
            })
        }

        override func didReceiveMemoryWarning() {
            super.didReceiveMemoryWarning()
            // Dispose of any resources that can be recreated.
        }





        override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

            return postData2.count

        }

        override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
            let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
            cell.textLabel?.font = UIFont.init(name: "Helvetica", size: 23)
            cell.textLabel?.text = postData2[indexPath.row]
            cell.detailTextLabel?.text = postData3[indexPath.row] + " ♥"
            cell.detailTextLabel?.textColor = UIColor.red;
            cell.detailTextLabel?.font = UIFont.init(name: "Helvetica", size: 23)
//        cell.backgroundColor = UIColor.red;
            return cell

        }

        override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat
        {
            return 80
        }

    }

    class tableData {
        var boothName: String
        var boothRating: Int
        init(boothName: String, boothRating: Int) {
            self.boothName = boothName
            self.boothRating = boothRating
        }
}

Answer 1

A simple way is to have an conditional check to see if the indexPath.row value is within the last five.

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
    if(indexPath.row >= postData2.count-5){
        cell.backgroundColor = UIColor.red
    }else{
        cell.backgroundColor = UIColor.white /* Remaining cells */
    }
    return cell
}

Answer 2

Some of the other answers will work - but it is nicer to use cells that have a known configuration when they are dequeued by cellForRowAt, not deal with a bunch of possible starting conditions each time you dequeue a cell. To do this subclass the UITableViewCell and override prepareForReuse(). This function will be called just before a cell is returned by dequeueReusableCell. Then cells can be set to a known starting point before you configure them. If cells could be received configured any possible way in cellForRowAt, you soon wind up with a very long function with a lot of if/else conditions.

The condition

if indexPath.row >= postData2.count - 5 {
    cell.backgroundColor = UIColor.red
}

can be used as it is, and prepareForReuse takes care of the cells not keeping any settings when they are recycled. Here's an example:

override func prepareForReuse() {
    super.prepareForReuse()
    backgroundColor = UIColor.white
}

With this one simple setting it's a wash whether you do the if/else approach or use subclassing to make the most of prepareForReuse. But as soon as you have more than one thing to set in a cell you will find it is far less complex to use this function and results in far fewer mistakes with the appearance of cells - consider what would happen if there were more than one possible color a cell could be, or there were multiple elements in the cell to be configured with multiple possible values...